1. Field of the Invention
The present invention relates to a method of manufacturing a liquid ejection head for ejecting liquid such as ink.
2. Description of the Related Art
Factors which greatly influence characteristics of a liquid ejection head include an ejection orifice, positional relationship between an ejection energy generating element and the ejection orifice, and internal structure of an ink flow path. This is because the volume, the velocity, and the direction of an ejected ink droplet are determined by the above-mentioned positional relationship, flow resistance in the ink flow path, the weight of the ink, and the like. Among these, as factors with regard to the flow resistance, the ejection orifice and the internal structure of the ink flow path are important. With regard to the internal structure of the ink flow path, it is known that, by providing a step in a part of the ink flow path, the velocity and the amount of the ejected ink may be controlled and ink may be ejected with stability.
Japanese Patent Application Laid-Open No. H05-124208 discloses a method in which a step is provided on a side opposed to a substrate surface of an ink flow path (hereinafter, referred to as ink flow path upper side). In the method disclosed in Japanese Patent Application Laid-Open No. H05-124208, by forming a mold material for the ink flow path on a substrate using a photolithography process or the like, providing a mask layer on the mold material, and selectively removing a part of the mold material which is not covered with the mask layer, a fluid resistance portion is formed on the ink flow path upper side.
Further, Japanese Patent Application Laid-Open No. 2004-042398 proposes a method in which, by using on a substrate multiple mold materials formed of different organic resins and repeating photolithography processes, multiple steps to be fluid resistance portions are provided in an ink flow path.
Study by the present inventors has revealed that, in the method disclosed in Japanese Patent Application Laid-Open Nos. H05-124208 or 2004-042398, when the mask layer or an upper side organic resin is selected, it is necessary to select a material which may be patterned without dissolving a mold material directly provided on the substrate and which may be adhered to the mold material.
Further, when an active ray is used in patterning the mask layer or the upper side organic resin, the process is restricted accordingly. For example, patterning is required to be performed in a wavelength range which is different from that of an active ray used in patterning the mold material directly provided on the substrate.